A common apparatus used by the airline industry is an electronics module. Each electronics module is connected to other equipment by cables. An electronics module utilizes a common device, to make and break these cable connections, called a cable connector.
One category of electronics module contains equipment which operates a variety of functions in an aircraft passenger cabin. There is typically one electronics module for each row of passenger seats on an airliner. In a commercial airliner an electronics module is commonly mounted under a seat, and therefore is inconvenient or awkward to reach.
During flight, aircraft undergo a significant amount of vibration. Therefore, the electronics modules should be securely fastened to the aircraft and the cable connectors should be securely fastened to the electronics module. The electronics modules and the cable connectors, however, also require testing, repair and replacement, and therefore must be removable. For these purposes different designs are now in use as will be explained shortly.
First, however, it should be noted that such removal of electronics modules is quite frequent. It must also be recognized that in the airline industry profit is made only by flying, and enormous loss or expense is incurred whenever aircraft must remain on the ground because of testing and repair.
Of course many spare modules can be kept available, so that a jetliner need not be delayed for the entire duration of testing and repair of a malfunctioning electronics module. Nevertheless the sensitivity of airline operations to idle time is so great that even a few minutes' delay for removal or replacement--or for the availability of a highly trained technician to perform such procedures--represents monumental cost.